Recently, liquid crystal display widely used for displaying element is constituted by a liquid crystal layer and a polarizing plate. The polarizing plate is constituted by arranging a transparent protecting layer on both sided of the polarizing film. The liquid crystal cell includes a liquid crystal layer and a substrate sandwiching the liquid crystal layer. In the case of a transmission type liquid crystal display, the polarizing plates are arranged on both sides of the liquid crystal cell. Various displaying modes such as TN (twisted nematic), VA (vertically aligned), IPS (in-plane switching) and OCB (optically compensatory bend) have bee proposed for the liquid crystal cell.
Regarding the liquid crystal display, there is a problem such as that the displaying ability is lowered when the displayed image is viewed in an oblique direction even though the image is suitably viewed when the image is viewed from the front of the display because the liquid crystal material and the polarizing plate each has anisotropism. Accordingly, various optical films for expanding the viewing angle of the liquid crystal display have been proposed; cf. Patent Documents 1 through 5.
Hitherto, the double refraction of the optical film is controlled for obtaining the desired viewing angle of the liquid crystal display. However, the birefringence required to the optical film is different depending on the displaying mode of the liquid crystal cell. Consequently, the birefringence cannot be sufficiently controlled by the usual method for controlling the birefringence of the optical film and the sufficient viewing angle cannot be provided.    Patent Document 1: Japanese Patent Publication Open to Public Inspection (hereafter referred to as JP-A) No. 4-127103    Patent Document 2: JP-A No. 2005-105139    Patent Document 3: JP-A No. 2005-105140    Patent Document 4: JP-A No. 2005-139304    Patent Document 5: JP-A No. 2005-139764